Several models have been proposed to explain the effects of mindfulness training on health and well-being, including several potential mechanisms. The goal of the present study is to empirically test a model of mindfulness mechanisms by comparing samples of meditators and non-meditators. Multi-sample path structural equation models were estimated and tested in two samples, one with 386 meditators and the other with 284 participants with no meditation experience. Results showed higher scores on the five mechanisms in the sample of meditators compared to non-meditators. It showed a greater effect of attentional control on body awareness and non-reactivity and of body awareness on non-reactivity, in meditators compared to non-meditators. The effect of attentional control on reappraisal, however, was lower for this group. The model was useful for explaining mindfulness in both meditators and non-meditators, and it was sensitive in identifying the elements of the process that differ in these two collectives. This study offers preliminary evidence about the important role of body awareness as a key mechanism in mindfulness. Therefore, body awareness should be included in future models designed to understand the underpinnings of mindfulness.